Have resetInternalsObject() handle detached documents.

Source/core/testing/v8/WebCoreTestSupport.cpp

 /*
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 48 matching lines @@
 }
 
 void resetInternalsObject(v8::Local<v8::Context> context)
 {
     // This can happen if JavaScript is disabled in the main frame.
     if (context.IsEmpty())
         return;
 
     ScriptState* scriptState = ScriptState::from(context);
     ScriptState::Scope scope(scriptState);
-    Page* page = toDocument(scriptState->executionContext())->frame()->page();
+    Document* document = toDocument(scriptState->executionContext());
+    ASSERT(document);
+    LocalFrame* frame = document->frame();
+    // Should the document have been detached, the page is assumed being destroyed (=> no reset required.)
+    if (!frame)
+        return;
+    Page* page = frame->page();
     ASSERT(page);
     Internals::resetToConsistentState(page);
     InternalSettings::from(*page)->resetToConsistentState();
 }
 
 }